Signaling system



Aug. 26, 1941. c. E. LoMAx SIGNALING SYSTEM 3 Sheets-Sheet 1 INVEMQR. I Clarence E.' Lam az BY M, dhd31 ATTORNEYS'.

Aug. 26, 1941.l c. E. LoMAx SIGNALING SYSTEM 3 Sheets-Sheet 2 Filed May 22, 1939 Aug, 26, 1941. c. E. LoMAx SIGNALING SYSTEM Filed May 22, 1939 3 Sheets-Sheet 3 @Saw MNRUSN @SQQQ n NSW SS www wb INVENTOR. Clarence E L omar ATTORNEYS.

Patented Aug. 26, 1941 Unir sTATEs PATENT OFFICE 2,253,714 sioNALINo SYSTEM Clarence E. Lomax, Oak Park, Ill., assgnor to Associated Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware x Application May 22, 1939, Serial No. 274,901

Y alarm lines extending to various alarm stations 7 Claims.

The present invention relates to signaling systems and, more particularly, to lire alarm systems.

A fire alarm system conventionally comprises a dispatcher station or central oince, a number oi engine stations or houses, a plurality of alarm stations or fire boxes and a plurality of alarm lines, eachV of the alarm lines being arranged to connect a number of the alarm stations and at least one of the engine stations in series circuit relationship With the central oiiice. Each alarm station is provided with a sender operative to send a signalv over the associated alarm line; each of the engine stations is provided with a sender operatively connected tothe associated alarm line; and the central office comprises sending apparatus operatively associated with the various alarm lines. Also', each engine station includes a receiver operatively connected to the associated alarm line; while the central oiiice comprises receiving apparatus operatively associated with the various alarm lines. The system is so connected and arranged that an alarm may be sent over any one of the alarmlines by opv erating the sender at any one ci the alarm stations associated with the alarm line. Fur-thermore, messages may be sent over any one of the alarm lines by operating the sender at any one ci the engine stationsv associated with the alarm line and by operating the sending apparatus at the central cnice. Alarms and messages sent over the alarm lines are recorded bythe receivers at the engine stations associated with the alarm lines and by the recording apparatus at the central ofce. l

While a re alarm system of the type vdescribed operates reasonably satisfactorily inservice, the installation and maintenance costs thereof are greater than are desirable due primarily to the fact that it is necessary for each alarm line in the system to extend directly to the central oice. Although this objection is slight when the system servesY a relatively small area, it is very serious when the system serves a relatively large area.

Accordingly, it is an object of the present invention to provide in a signaling system including a central oiiice and a plurality of stations,

a signaling system of the type described, an l improved repeater arrangement for operatively interconnecting a relatively large number of repeater.

and a trunk line extending to a central oice.

Another object of the invention is to provide ina repeater terminating a group of signal lines,

an improved arrangement for receiving a signal sent over anyone of the signal lines in the group and for repeating corresponding sign-als over the other signal lines in the group.

A further object of the invention is to provide in a repeater terminating a trunk line and two groups of signal lines, an improved arrangement adapted to receive a signal sent over the trunk line and repeat corresponding signals over the signal lines'in the two groups, and to receive a signal sent over any one of the signal lines in one of thegroups and repeat corresponding signals over the trunk line and over the signal lines inthe other group. Y

A further object'of the invention is to provide a signaling system comprising a plurality of signal lines having senders associated therewith, a trunk line, a repeater operatively interconnecting the signal lines and the trunk line, and an improved arrangement incorporated in the various senders and in the repeater for preventing interference between the various senders.

rtrated as being incorporated in a signaling system, adapted to serve a relatively large general area divided into sublareas, comprising a central oice disposed at any convenient place in the vgeneral area; repeater stations disposed in the respective subareas; and engine, test and alarm stations disposed in the various subareas. A repeater is provided at each repeater station and terminates a trunk line extending to the central office. Also, each of the repeaters terminates a first group of signal or box lines anda second group of signal or combination box and alarm lines. Each of the box lines connects a number of alarm stations and at least one test station, in thersubarea, in series circuit relationship With the repeater; while each of the combination box and alarm lines connects a number of alarm stations and at least one engine station, in the subarea, in series circuit relationship with the The central oii'ice comprises sending tion, each of the repeaters is so connected and.

arranged that it is operative to receive a signal sent over any one of the signal lines in either the iirst or the second groups extending thereto and repeat a corresponding signal over the trunk line extending therefrom to the central oice. Also, the repeater is so connected and arranged that it is operative to receive a signal sent over the trunk line extending thereto and repeat corresponding signals over the signal lines in the first and the second groups extending therefrom. Moreover, each of the repeaters is so connected and arranged that it is operative, when a signal is sent over any one of the box lines extending thereto, to repeat corresponding signals over the combination box and alarm lines extending therefrom. Finally, each one of the repeaters is so connected and arranged that it is operative, when a signal is sent over any one of the combination box and alarm lines extending thereto, to repeat corresponding signals over the other combination box and alarm lines extending therefrom. Y

More particularly, the trunk line, each of the box lines and each of the combination box and alarm lines terminating at a given repeater are provided with individual line circuits. Each of the line circuits comprises an impulse relay and a timing relay, the impulse relay being provided with an operating circuit and a holding circuit. The line circuit is so connected and arranged that the operating circuit of the impulse relay is controlled in accordance with signaling impulses sent over the associated line, thereby normally to cause the impulse relay to operate intermittently. Means is provided which is controlled by the intermittent operation of any one of the impulse relays for controlling the associated one of the timing relays. Each of the timing relays is operative to effect the interruption of a point in the holding circuit of the associated impulse relay and to eiect the completion of the holding circuits of the other impulse relays, thereby to prevent intermittent operation of the other impulse relays. A repeating device is included in the repeater and is controlled in accordance with the intermittent operation of the one impulse relay; and means is provided which is controlled by the one timing relay after the signaling impulses have been sent over the associated line for interrupting the holding circuits of the other impulse relays, thereby to condition the other impulse relays to be operated intermittently.

Furthermore, each of the line circuits is so connected and arranged that the operating circuit of the impulse relay therein is interrupted in the event the associated line is subjected to an open circuit fault, thereby to cause the impulse relay to remain restored. A timer is provided which is controlled in the event the impulse relay remains restored a predetermined time interval for completing the holding circuit of the impulse relay, thereby to prevent intermittent operation` thereof. Finally, the line circuit comprises means controlled when the line associated therewith is recompleted for interrupting the holding circuit of the impulse relay, thereby to recondition the impulse relay to be operated intermittently.

In accordance with a further feature of the invention, each of the repeaters comprises normally effective control means for rendering the repeater controllable over the trunk line or any one of the signal lines terminating thereat, means governed when the repeater is rendered controllable over the trunk line or any one of the signal lines terminating thereat for rendering ineffective the control means, and means controlled after the signal has been sent over the trunk line or the one signal line terminating thereat for rendering again effective the control means. The sender at each of the alarm stations comprises normally effective means for sending a signal over the associated signal line and means governed when a signal is being sent over the associated signal line for rendering ineffective the last-mentioned means. The connection and arrangement of the repeater in conjunction with the type of sender utilized at each of the alarm stations positively prevents interference between the senders and interference with the repeater when the repeater is busy.

Further features of the invention pertain to the particular arrangement of the circuit elements of the signaling system whereby the aboveoutlined and additional features are attained.

The novel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which Figures l to 3, inclusive, taken together, illustrate diagrammatically the details of a signaling system having incorporated therein the present invention.

Referring now more particularly to Figs. 1 to 3, inclusive, of the drawings, the signaling system there illustrated comprises a central office 50, a number of repeater stations, including the repeater station 69, and a number of alarm trunks respectively extending between the central oiiice and the repeater stations, including the alarm trunk Sill extending between the central office 5H and the repeater station EB. Each of the repeater stations is provided with a repeater; and a group of box lines and a group of combination box and alarm lines terminate at each of the repeater stations. For example, the repeater station Eil is provided with the repeater 200; the group of box lines terminating at the repeater station Bil includes the box line itt; and the group of combination box and alarm lines terminating at the repeater station includes the combination box and alarm lines H5 and 2%.

Each of the box lines is of the series type and connects a test station and a plurality of alarm stations or re boxes in series circuit relationship. For example, the series box line i connects the test station iii and the fire boxes H33, lid, 105, etc., in series circuit relationship. Also, each of the combination box and alarm lines is of the series type and connects a 4plurality of engine stations and a plurality of alarm stations or nre boxes in series circuit relationship. For

example, the series combination box and alarm line I I connects the engine stations 15, 80, etc., and the fire boxes I8, H0, |20, etc., in series circuit relationship. The alarm trunk, each .of the box lines, and each of the combination box and alarm lines terminating at a given repeater station are provided with line circuits individual thereto at the repeater station, which line circuits are o-peratively associated with the repeater thereat, the alarm trunk 30| the box line |00 and the combination box and alarm lines I |5 and 260 terminating at the repeater station 60 being respectively provided with the line circuits 320, I 30, |60 and 205 individual thereto at the repeater station 00, which line circuits are operatively associated With the repeater 200 thereat.

Preferably, the signaling system serves a general area divided into a plurality of subareas.

The central ofce 50 is disposed at a convenient place in the generalV area; While the repeater stations are respectively disposed in the various subareas, the repeater station 00 being disposed in a particular subarea. Furthermore, the test station 10, etc., the engine stations 15, S0, etc., and the alarm stations |03, |04, |05, ||8, H9, |20, etc., are disposed in the particular subarea wherein the repeater station 00 is'disposed.

The central office 50 comprises a recorder or printer and a sending key individually associated with each alarm trunk terminating thereat, the printer P390 and the sending keyv K306'atthe central omce 50,.shown on the right-hand side of Fig. 3, being individually* associated with the alarm trunk 30| terminating thereat. i Each of the test stations comprises a recorder or printer and a sending key associated with the box line extending thereto, the printer PI l0 and the sending key K10!! at the test station 10, shown on the left-hand sidev of Fig. 1, being individually associated with the box line |00 extending to the test station 10. Also, each of the engine station comprises a recorder or printer and a sending key associated with the combination box and alarm line extendingthereto, the printer PI 26 and the sending key K|25 at the engine stationr 15, shown on the left-hand side of Fig. 1, being associated withthe combination box and alarm line H5 extending to the engine station 15. It is noted that each of the engine stations is provvided with the usual fire-fighting apparatus; While each of the test stations may be provided with some fire-iighting apparatus. Furthermore,

a central dispatcher or nre marshal supervises the apparatus at the central oice and coordinates the activities of the various engine and test stations. 1

Each of the re boxes, such, for example, as the fire box |04, shown Von the lett-hand side of Fig. 1, is of the well-known series non-interfering type and is so constructedand arranged that when the operating lever thereat is operated, the re box ordinarily operates immediately and automatically to transmit over the associated line, a number of times, a code corresponding to the particular fire box, Furthermore, the fire box is so connected and arranged that it does not operate immediately to 'transmit in the event that the associated linefis busy, but delaysv the transmission until the associated line becomes idle. Y

Preferably, the repeater at'each of therepeater stations is connected and arranged in the manner of the repeater 200 at the repeater station 60, which comprises, as shown in Fig. 2, con-Q ventionaltiming apparatus TA205, a start relay battery |31.

R2| 0, a first impulse relay R220, a second impulse relay R230, a test relay R240 and a control relay R250. Preferably, the line circuits at each of the repeater stations are connected and arranged in an .identical manner. For example, the line circuit |30 at the repeater'station 50 and individuallyassociated with the'box line |00 comprises, as shown on *the right-hand side of Fig. 1, a lockout relay R|35, a line relay R|40, an'impulse relay R|45, a timing relay R|50 and a control relay R|55; the line circuit |00 at the repeater station 60 and individually associated with the combination box and alarm line ||5 comprises, as shown on the right-hand side of Fig. 1,- a lockout relay R|65, a line relay R|10, an impulse relay R|15, a timing relay R| and a control relay R|; and the line circuit 320 at the: repeater station 60 and individually associated with the alarm trunk 30| comprises, as shownon the left-hand side of Fig. 3, a control relay R330, a timing relay R335, an impulse relay R340, a line relay R345 and a lockout vrelay R350.

Theconnection and arrangement of the signaling system will best be understood from a consideration of the description of the operation thereof yappearing hereinafter.

l The alarm trunk 30| is included in a normally completed series circuit extending from one terf minal of the battery 360 by Way of C304, the Winding of the printer magnet PM3I| of the printer P3|0 at the central oiiice 50, the sending key K305 at the central office 50, C305, the wind-r ing of the line relay R345, C362, RA225 and 030| tothe other terminal of the battery 300. The box line |00 is included in a normally completed series circuit extending from one terminal of the battery 31 by way of C|00, RAZZI and the multiple connected strap S221, RA230, CISI, the Winding of the line relay R|40, C|02, the sending key K|08 at the test station 10, the Winding of the printer magnet PM| of the printer PI l0 at the test station 10, the fire boxes |05, I 04, |03, etc., and C|0| to the other terminal of the The combination box and alarm yline ||5 is included in a normally completed series circuit extending from one terminal of the `battery |61 by way of C|02, RA224, RA232, Cm3, the windingA of the line relay R|10, C||1, the sending keyKI25 at the engine station 15, the winding of the printer magnet PM|21 of the printer P|26 at the engine station 15, the re boxes |20, ||9, ||8, etc., apparatus in the engine station 00, and CI I6 to the other terminal of the batteryY |61.

Accordingly, the line relay R345=in the line circuit 320 individually associated With the alarm trunk 30|: normally occupies its operated position, thereby to retain completed, at RA345 and RC341, ,an obvious circuit-for energizing the lower windingof the impulse relay R340 in order to retain the last-mentioned relay in its operated position. Also, the line relay RI 40 in the line circuit |30 individually associated with the box line |00 normally occupies its operated position, thereby to retain completed, at RA|4|` and RCl42, an obvious circuit for energizing the lower Winding of the impulse relay R|45 in order to retain the last-mentioned relay in its operated position. Similarly, the line relay R|10 in the line circuit |00 individually associated with the combination box and alarm line 5 normally occupies its operated position, thereby to retain completed, at RAI1| and RC|12, an obvious circuit'for energizing the lower winding of the impulse relay R|15 in order to retain the last-mentioned relay in its operated position.

In order to initiate an alarm on one of the box lines, such as the box line |00, the operating lever at one of the nre boxes included in the line, such as the operating lever of the re box included in the box line |00, is operated. In the event the box line |00 is idle at this time, when the operating lever of the fire box |04 is operated, the iire box |04 operates immediately to transmit, a number of times, a code individually corresponding to the re box |04, this code including a number of digits, each including one or more impulses. On the other hand, in the event the box line |00 is busy at this time, when the operating lever of the ire box |04 is operated, the fire box I 04 does not operate immediately to transmit the code but delays the transmission of the code until the box line |00 becomes idle. In transmitting the code, the re box |00 rst interrupts at the switch S|01 the previously traced series circuit including the box line |00, thereby to cause the line relay R|40 in the line circuit |30 individually associated with the box line |00 t0 restore. Upon restoring, the line relay RUN) interrupts, at RAI4I and RCI02, a point in the previously mentioned circuit for energizing the lower winding of the impulse relay Ridand prepares, at RAMI and RCMS, a point in a holding circuit, traced hereinafter, for energizing the upper winding of the lockout relay Ri' in series with the lower winding of the impulse relay RM5. When the previously mentioned circuit for energizing the lower Winding of the impulse relay R|0-5 is interrupted, the last-mentioned relay restores, thereby t0 inter- -rupt, at RAifz, a point in a holding circuit, traced hereinafter, for energizing the upper winding thereof, to prepare, at RAI 00, a circuit, traced hereinafter, for energizing the winding of the nrst impulse relay R220 in the repeater 200, and to complete, at RAI/31, an obvious circuit for energizing the Winding of the timing relay RI50. When the winding of the timing relay REE!) is thus energized, this relay operates, thereby to complete, at RA|53 and RCI`52, RCIEI, an 010--A vicus circuit for energizing the winding of the control relay Ri, thereby to cause the latter relay to operate.

Upon operating, the control relay R455 coming, the control relay R555 completes, at RAISS,

a connection between the conductors C190 and CESI of the box line |00, thereby vto short-circuit the portion of the box line |00 extending into the repeater 200. It is noted that the portion of the box line |00 extending into the repeater 200 is shortcircuited, thereby positively to prevent the operation of the repeater from causing impulses to be transmitted from the repeater 200 back over the box line |00. Furthermore, the control relay R|55 interrupts, at RAI51, a point in a holding circuit, traced hereinafter, for energizing the upper winding of the impulse relay RME, prepares, at RA|50, a further point in the previously mentioned circuit for energizing the winding of the first impulse relay R220 in the repeater and completes, at RA|`59, an obvious circuit for energizing the winding of the start relay R2|0 in the repeater 200, thereby to cause the last-mentioned relay to operate.

Upon operating, the start relay R2| 0 com- 75 pletes, at RA2|4, a holding circuit for energizing the upper winding of the impulse relay R|15 in the line circuit |60 individually associated with the combination box and alarm line H5, this circuit extending from ground by way of RA2I4, CIGI, RAI81, RAI15 and the upper winding of RI15 to battery. Also, the start relay R2 I0 completes, at RA2|5, a holding circuit for energizing the upper winding of the impulse relay R340 in the line circuit 320 individually associated with the alarm trunk 30|, this circuit extending from ground by way of RA2|5, C363, RA334, RA342 and the upper Winding of R340 to battery. Similarly, the start relay R2I0 completes, at RAZIS, etc., holding circuits for respectively energizing the upper windings of the start relays in the line circuits 205, etc., individually associated with the combination box and alarm lines 260, etc. Accordingly, at this time, the box line |00 has seized the repeater 200 and the start relay R2I0 in the repeater 200 has operated to complete holding circuits for retaining the impulse relays in the line circuits individually associated with the other box lines, the combination box and alarm lines and the alarm trunk associated with the repeater 200 in their operated positions.

Also, upon operating, the start relay R2 I0 completes, at RA2I3, the previously mentioned circuit for energizing the Winding of the iirst impulse relay R220, this circuit extending from ground by way of RAME, RAI58, C|32, RAZ I3 and the winding of R220 to battery. When energized over the above-traced circuit, the first impulse relay R220 operates, thereby to interrupt, at RA224, a point in the previously traced series circuit including the combination box and alarm line I |5, to interrupt, at RAZZE, etc., points in the previouslytraced series circuits including the combination box and alarm line 200, etc., and to interrupt, at RA225, a point in the previously traced series circuit including the alarm trunk 30|. Furthermore, it is noted that the rst impulse relay R220 interrupts, at the contacts RA22I and at similar contact points, the series circuits including the box line |00 and the other box lines. However, this operation of the contacts RA22| and the corresponding contacts is without effect in view of the fact that the contacts RA22I are short-circuited by the Strap S221 and the corresponding contacts are short-circuited by corresponding straps in a similar manner.

In view of the above description of the box line |00 and the combination box and alarm line IIS, it will be apparent that the box line |00 may be readily converted into a combination box and alarm line merely by cutting the strap S221 and that the combination box and'alarm line I I 5 may be readily converted into a box line merely by adding a strap short-circuiting the contacts RA224 included in series circuit relation therewith.

From the foregoing it is apparent that the operation of the rst impulse relay R220 in the repeater 200 interrupts the series circuits including the alarm trunk 30| and each of the combination box and alarm lines associated with the repeater 200; however, it does not interrupt the series circuits including the box lines. Thus, it will be apparent that the operation of the start relay R2 I0 in the repeater 200 has the effect of rendering the alarm trunk 30|, each of the box lines, and each of the combination box and alarm lines busy; While the operation of the first impulse relay R220 in the repeater 200 has the effect of rebeating the code received frbrn the re box |04 by way of the box line over the alarm trunk 30| and each of the combination box and alarm lines.

Continuing now with the operation of the apparatus included in the signaling system incident to the interruption of the previously traced series circuit including the box line |00, when this series circuit is interrupted, the circuit for energizing the Winding of the printing magnet PMI of the printer PI I0 at the test station 10 is interrupted, thereby to cause the printer magnet PMI I to restore. When the printer magnet PMI I I restores, the armature PAI I2 thereof is released, thereby to cause the stylus operatively associated with the armature PAI I2 to mark the associated moving tape ||3. When the previously traced series circuit including the alarm trunk 30| is interrupted, the circuit for energizing the winding of the printer magnet PM3|| of the printer 3|0 at the central oflice 50 is interrupted, thereby to cause the printer magnet PM3|| to restore. Upon restoring, the printer magnet PM3I I releases its armature PASIZ, thereby to cause the stylus operatively associated with the armature PA3|2 to mark the associated moving tape 3 |3. Also, when the previously traced series circuit including the combination box and alarm line II5 is interrupted, the circuit for energizing the winding of the printer magnet PMIZ'I of the printer PI26 at the engine station 'I5 is interrupted, thereby to cause the printer magnet PM|2`| to restore. When the printer magnet PM|2'| restores, it releases its armature PA|28, thereby to cause the stylus operatively associated with the armature PA|28 to mark the associated moving tape |29.

The re box |04 then operates to complete at the switch S|0`| the previously traced series circuit including the box line |00, ythereby to cause the line relay R|40 in the line circuit |30 individually associated with the box line |00 to reoperate. When the line relay R|40 reoperates, it completes, at RAMI and RCMZ, the previously mentioned circuit for energizing the lower winding of the impulse relay RMS, thereby to cause the last-mentioned relay to reoperate. WhenA the impulse relay RI45 reoperates, it interrupts, at RAM'I, the previously mentioned circuit for energizing the winding of the timing relay R|50, thereby to cause the latter relay to restore. When the timing relay RI 50 restores, it sets the weighted armature RA|53 thereof into Vibration, whereupon the weighted armature RA|53 alternately engages the associated contacts C|52 and C|54 in order to complete intermittently the previously traced holding circuit for energizing the winding of the control relay RI55. The control. relay R155, being of the slow-to-release type, does not restore due to the fact that the previously traced holding circuit for energizing the Winding thereof is intermittently completed. Furthermore, upon reoperating, the impulse relay R|45 interrupts, at RAIliB, the previously traced circuit for energizing the winding of the first impulse relay R220 in the repeater 2190, thereby to cause the last-mentioned relay to restore. Upon restoring, the rst impulse relay R220 recompletes, at RA224, the previously traced series circuit including the combination box and alarm line ||5, re-v etc.

When the previously traced circuit including the box line |00 is recomp-leted, the printer magnet PMITII of the printer PI I0 at the test station 'I0 reoperates, thereby to cause the stylus operatively associated with the armature PAI I0 to disengage the associated moving tape ||3. Also, when the previously traced series circuit including the' combination box and alarm line ||5 is recompleted, the printer magnet PM|2'| of the printer PI26 at the engine station 75 reoperates,`

thereby to cause the stylus operatively associated with the armature PAI28 todisengage the associated moving tape |29. Similarly, when the previously traced series circuit including the alarm trunk 35| is recompleted, the printer magnet PMSH of the printer P3I0 at the central oflice 5B reoperates, thereby to cause the stylus operatively associated with the armature PA3I2 to disengage the associated moving tape 3I3.

It is noted that the line relay RMD in the line circuit |30 individually Vassociated with the box line |00 follows the impulses of the digits comprising the code transmitted from the re box |04 vover the box line |00, this relay operating `each time the previously traced series circuit including the box line |00 is completed, and this relay restoring each time this series circuit including the box line |00 is interrupted. The line relay RMU follows the impulses transmitted over the previously traced series circuit including the box line I 00 and repeats these impulses to the impulse relay R|45, which last-mentioned relay f repeats these impulses to the iirst impulse relay R220 in the repeater 200. The first impulse relay R220 in the repeater 255 repeates the impulses over the alarm trunk 35| and over each of the combination box and alarm lines in the previously described manner. Accordingly, the printer PI It atthe test station T0 included in the box line Iiiil, the printer P3|0 at the central office 55 included in the alarm trunk 30E, the printer PI26 at the engine station '15 included in the combination box and alarm line H5, and the other printers at the engine stations included in the other combination box and alarm lines operate to record the code transmitted, a number of times, fron-1 the particular fire box |54. Furthermore, it is noted that while the code is beingA transmitted, a number of times, from the fire box |04, the control relay Ri55 in the line circuit |30 individually associated with the box line lill? remains in its operated position, thereby to cause the start relay R2 i 0 in the repeater 205 to remain in its operated position. The operated start relay R2ii in the `repeater 200 retains the impulse relays in the line circuits individually associated with the alarm trunk 30|, the combination box and alarm lines, and the other box lines, with the exception of the box line |05 upon which the alarml is initiated, in their operated positions, thereby effectively to retain busy the alarm trunk 30|, each of the combination box and alarm lines and each of the box lines.

After the fire box |04 has operated to transmit the corresponding code, a number of times, over the previously traced series circuit including the box line |00, operation thereof is arrested and the previously traced series circuit including the box line |00 is reoompleted, thereby to arrest further operation of the line relay RM!) in the line circuit |30 individually associated with the box line |00. When the operation of the line relay R|40 is arrested, the operation of the impulse relay R|45 and the timing relay R|5il is arrested.

- Shortly thereafter, thefweighted armature RAI 53 of the timing relay R|50 assumes a position of rest disposed intermediate the associated contacts R|52 and R0l5il, thereby to interrupt the previously traced holding circuit for energizing the Winding of the control relay Ri 55. Shortly thereafter, the control relay Rl 55 restores to complete, at RAl l", the previously mentioned holding circuit for energizing the upper Winding of the impulse relay Rld, this circuit extending from ground by Way of RA'ii, 0|3l, RAIET, RAl and the upper Winding of R|45 to battery. Also, the control relay Rl55 interrupts, at RAIEQ, the previously mentioned circuit for energizing the start relay B2i@ in the repeater 200 in order to cause the last-mentioned relay to restore. Upon restoring, the start relay RZHI interrupts, at RANA, the previously traced holding circuit for energizing the upper winding of the impulse relay Rll in the line circuit |60 individually associated with the combination box and alarm line H5, interrupts, at RAME, the previously traced holding circuit for energizing the upper Winding of the impulse relay R340 in the line circuit 320 individually associated with the alarm trunk 30|, and interrupts, at RA2|5, etc., the holding circuits for energizing the upper windings of the impulse relays in the line circuits 265, etc., individually associated with the combination box and alarm lines etc. Also, the start relay R2|0 interrupts, at RA2| l, the previously traced holding circuit for energizing the upper Winding of the impulse relay R335 in the line circuit |30 individually associated with the box line |00 and interrupts the other holding circuits for energizing the upper windings of the impulse relays in the line circuits individually associated with the other box lines.

Furthermore, when the control relay R|55 restores, it interrupts, at RA|55, a further point in the previously traced holding circuit for energizing the winding thereof, interrupts, at RAl58, a further point in the previously traced circuit for energizing the Winding of the first impulse relay RElil in the repeater 200, and interrupts, at RAI 50, the previously mentioned path for shortcircuiting the portion of the box line |00 extending into the repeater 200.

At this time, the repeater 200, the alarm trunk 30|, each of the box lines and each of the combination box and alarm lines are idle and available for further use.

In View of the foregoing description of the manner in which an alarm is initiated at the iire box |04 on the box line |00, it will be understood that an alarm may be initiated at any one of the lire boxes on the associated box or combination box and alarm line and that the code transmitted over the associated line to the repeater 200 will be repeated thereby over the alarm,

trunk 33| and over each of the combination box and alarm lines, but not over the box lines, as previously explained. Specifically, it will be understood that when an alarm is initiated at the fire box H9 on the combination box and alarm line H5, the line circuit |00 individually associated with the combination box and alarm line i i5 will operate in a manner similar to the operation of the line circuit |30 individually associated With the box line H0, as previously explained, thereby to cause the repeater 200 to repeat the code over the alarm` trunk 30| and over each of the other combination box and alarm lines.

Furthermore, it Will be understood that an alarm or other message may be transmitted from the test station 13 over the box line |00 by operating the sending key KI 50 at the test station 10 and that this alarm or message will be repeated by the repeater 200 in the previously described manner over the alarm trunk 33| and over each of the combination box and alarm lines, but Will not be repeated over the box lines. Similarly, it will be understood that an alarm or other message may be transmitted from the engine station 15 over the combination box and alarm line H5 by operating the sending key K|25 at the engine station 15 and that this alarm or message will be repeated by the repeater E00 in the previously described manner over the alarm trunk 30| and over each oi the other combination box and alarm lines, but will not be repeated over the box lines.

instructions may be transmitted from the central olce 50 over the alarm trunk 30d to the repeater 200 by operating the sending key K306 at the central oice 50 and repeated by the repeater 200 over each of the box lines and over each of the combination box and alarm lines terminating at the repeater 200. More Specically, the sending key K300 at the central office 50 is operated, thereby to interrupt and to complete alternately the previously traced series circuit including the alarm trunk 30 i. Each time the previously traced series circuit including the alarm trunk 30| is interrupted, the circuit for energizing the winding of the line relay R345 in the line circuit 320 individually associated with the alarm trunk 30| is interrupted, thereby to cause the last-mentioned relay to restore. Upon restoring, the line relay R3l5 interrupts, at RA346 and RC341, the previously mentioned circuit for energizing the lower Winding of the impulse relay R340, thereby to cause the lastmentioned relay to restore. Upon restoring, the impulse relay R340 prepares, at RA34I, a circuit, traced hereinafter, for energizing the second impulse relay R230 in the repeater 200, interrupts, at RA342, a point in a holding circuit, traced hereinafter, for energizing the upper Winding thereof, and completes, at RA343, an obvious circuit for energizing the winding of the timing relay R335. When the winding of the timing relay R335 is thus energized, this relay operates to complete, at RA338 and R033?, RC336, acircuit for energizing the Winding of the control relay R330, this circuit extending from ground by way of RA338, R033?, R033@ and the winding of R330 to battery. When energized over the above-traced circuit, the control relay R330 operates to complete, at RA330, a holding circuit for energizing the Winding thereof, this circuit extending from ground by Way of RA338, R033?, RA330 and the winding of R330 to battery. Also, the control relay R330 prepares, at RA33I, a further point in the previously mentioned circuit for energizing the Winding of the second impulse relay R230 in the repeater 200, interrupts, at RA334, a point in the previously traced holding circuit for energizing the upper .Winding of the impulse relay R300, completes, at

RA333, an obvious path for short-circuiting the portion of the alarm trunk 301 extending into the repeater 200, and completes, at RA332, an obvious circuit for energizing the winding of the start relay R2|0 in the repeater 300, thereby to cause the last-mentioned relay to operate.

Upon operating, the start relay R2 l 0 completes, at RA2| I, the previously traced holding circuit for energizing the upper Winding of the impulse relay R|45 included in the line circuit |30 individually associated with the box line |00, completes holding circuits for energizing the upper windings of the impulse relays in the line circuits individually associated with the other box lines, completes, at RA2|4, the previously traced circuit for energizing the upper Winding of the impulse relay R|'|5 in the line circuit |60 individually associa-ted with the combination box and alarm line H5, prepares, at RA2|5, a point in the previously traced holding circuit for energizing the upper winding of the impulse relay R340 in the line circuit 320 individually associated with the alarm trunk 30|, and completes, at RA2I0, etc., the holding circuits for energizing the windings of the impulse relays in the line circuit 265, etc., individually associated with the combination box and alarm lines 260, etc. At this time the impulse relays included in the line circuits individually associated With the box lines and with the combination box and alarm lines are retained in their operated positions, thereby effectively to maintain the box lines and the combination box and alarm lines busy as previously explained.

Also, upon operating, the start relay' R2|0 completes, at RA2|2, the previously mentioned circuit for energizing the second impulse relay R230, this circuit extending from ground by Way of RA34I, RA33I, C365, RA2|2 and the winding of R230 to battery. When energized over the above-traced circuit, the second impulse relay R230 operates to interrupt, at RA230, the previously traced series circuit including the box line |00, to interrupt the series circuits including the other box lines, to interrupt, at RA232, the previously traced series circuit including the combination box and alarm line H5, and to interrupt, at RA233, etc., the series circuits including the other combination box and alarm lines 260, etc.

When the previously traced series circuit including the box lineV is interrupted, the printer Pi l0 at the test station T0 included in the box line |00 operates as previously explained. Also when the previously traced series circuit inciuding the combination box and alarm line H5 is interrupted, the printer P520 and the engine station E5 operates as previously explained. In a similar manner, the -printers at the other test stations included in the box lines and the printers at the other engine stations included in the other combination and alarm lines are operated. Also, when the previously traced series circuit including the alarm trunk 30| is interrupted at the sending key X306, the printer P3|0 at the central oiiice 50 operates as previously explained.

'When the sending key X306 is returned to its cluding the other .box lines, completes, at RA232, the previously traced series circuit including the combination box and alarm line H5, and completes, at RA233, etc., the series circuits including the other combination box and alarm lines 250, etc- In vieW of the foregoing description, it will be apparent that the printers at the test stations and at the engine stations respectively associated with the box lines and with the combination boxy and alarm lines operate to record the message transmitted from the central office 50 by operating the sending key X305.

At the conclusion of the message transmitted from the central office 50, the sending key K306 is returned to its normal position, thereby to Vcause the line relay R345 in the line circuit 320 individually associated with the alarm trunk to remain in its operated position. The line circuit 320 then operates in a manner similar tothe operation of the line circuit |30 previously described, thereby to cause the control relay R330 to restore. Upon restoring, the control relay R330 interrupts, at RA330, the previously traced holding circuit for energizing the Winding thereof, completes, at RA334, the previously traced holding circuit for energizing the upper Winding of the impulse relay R340, interrupts, at RA333, the previously mentioned path for short-circuiting the portion of the alarm trunk 30| extending normal position, the previously traced series circuit including the alarm trunk 30| is reco-mpleted, thereby to cause the line relay R345 in the line circuit 320 individually associated with the ,alarm trunk 30| to reo-perate. Upon reoperating, the line relay R345 recompletes, at RA300 and RC341, the previously mentioned circuit for energizing the lower Winding of the impulse relay R340, thereby to cause the latter relay to reoperate. Upon reoperating, the impulse relay R340 interrupts, at RAMI, the previously traced circuit for energizing the Winding of the second impulse relay R230 in the repeater 200, thereby to cause the latter relay to restore. Upon restoring, the second impulse relay R230 completes, at RA230, the previously traced series circuit including the box line |00, completes the series circuits ininto the repeater 200, interrupts, at RA332, the previously mentioned circuit for energizing the Winding of the start relay R2I0 in the repeater 200, and interrupts, at RA33I, a further point in the previously traced circuit for energizing the Winding of the second impulse relay R230 in the repeater 200. The start relay R2|0 and the second impulse relay R230 then restores, thereby to render the repeater 200, the alanm trunk 30|, each ofv the box lines and each of the combination box and alarm lines idle as previously explained. In vieW of the foregoing description of the operation of the signaling system, it will be understood that .when the alarm trunk 30| is interrupted, the repeater 200 is seized by the 'alarm trunk 30| and is rendered busy to each of the box lines and each of the combination loo-x and alarm lines; and the repeater 200 is rendered effective to transmit impulses received by Way of the alarm trunk 30| o-ver each or the box lines and over each of the combination box and alarm lines. When one of the bo-x lines, such as the box line |00, is interrupted, the repeater 200 is seized `b-y the box line |00 and is rendered busy to the alarmtrunk 30|, each of the other box lines and each of the combination box and alarm lines; and the repeater 200 is rendered eiiective to transmit impulses received by Way or the box line |00 over the alarm trunk 30| and over each of the combination box and alarm lines. When one of the combination box and alarm lines, such as the combination box and alarm line H5, is interrupted, the repeater 200 is seized by the combination box and alarm line H5 and is rendered busy tothe alarm trunk 30|, each of the other combination box and alarm lines and each of the box lines; and the repeater 200 is rendered effective to transmit impulses received by way of the combination box and alarm line l5 over the alarm trunk 30| and over each of the other combination box and alarm lines.

Furthermore, it is noted that When the repeater 200is seized by the alarmtrunk 30|, the fire boxes associated With the box lines and with the combination box and alarm lines are rendered busy due to the fact that the repeater 200 operates at this time to repeat impulses over the box lines and over the combination box and alarm lines. Also, when the repeater 200 is seized by `one or" the box lines at a given one of the rire boxes associated therewith, the other of the iire boxes associated with the one box line and the nre boxes associated with the combination box and alarm lines are rendered busy due to the fact that the given re box sends impulses over the one box line and the repeater 200 operates at this time to repeat impulses over the combinati-on box and alarm lines. However, the nre boxes associated with the other box lines are not rendered busy due to the fact that the repeater 200 does not repeat impulses at this time over the other box lines- Accordingly, at this time, the fire boxes associated with the other' box lines may be operated in order to cause the printers at the test stations associated therewith to operate as previously explained. Similarly, when the repeater 200 is seized by one of the combination box and alarm lines at a given one of the nre boxes associated therewith, the other of the fire boxes associated with the one combination box and alarm line and the re boxes associated with the other of the combination box and alarm lines are rendered lbusy due to the fact that the given re box sends impulses over the one combination box and alarm line and the repeater 200 operates at this time to repeat impulses over the other of the combination box and alarm lines. However, the fire boxes associated with the box lines are not rendered busy due tothe fact that the repeater 200 does not repeat impulses at this time over the box lines. Accordingly, at this time the re boxes associated with the box lines may be operated in order to cause the printers at the test stations associated therewith to operate as previously explained.

In order to prevent sustained false seizure oi the repeater 20? due to the failure of one of the box lines, one of the combination box and alarm lines, or the alarm trunk 30I caused by an open circuit fault thereon, an arrangement is incorporated in the repeater 200 and the line circuits individually associated with the various box lines, combination box and alarm lines and the alarm trunk 30|. This arrangement comprises the test relay R240 and thecontrol relay R250 in the repeater 200 and the lockout relays in the Various line circuits.

In the event one of the box lines, such as the box line |00, is accidentally interrupted, an alarm is first initiated on the box line as previously explained, thereby to cause the start relay R2I0 and the first impulse relay R220 in the repeater 200 to operate. In this case, the rst impulse relay R220 in the repeater 2m) remains in its operated position and does not alternately restore and reoperate in the usual manner due to the fact that no impulses are being transmitted over the box line I. Upon operating, the rst start relay R220 completes, at RA222, a path for applying battery potential to the control conductor PI, this path extending from battery potential by way of the upper winding of R24-0 and RA222 to the control conductor Pl. This application of battery potential to the control conductor PI initiates the operation of timing apparatus TA205 which causes ground potential to be applied to the control conductor Pi after a predetermined time interval, thereby to complete a circuit for energizing the upper winding of the test relay R240, whereupon the test relay R240 operates. Upon operating, he test relay R240 completes, at RAMI, a holding circuit for energizing the lower winding thereof, this circuit extending from ground by way of RAEZB, RAMI and the lower winding of RMU to battery. Also, upon operating, the test relay R20@ prepares, at RAM?, a circuit for energizing the winding of the control relay R258, which circuit being completed automatically in the event the timing apparatus TAt associated with the control conductor PI is retained in its operated position for a predetermined time interval. In the last-mentioned event, ground potential is applied in the timing apparatus 'IA to the control conductor P2, thereby to complete the previously mentioned circuit for energizing the winding of the control relay R250, this circuit extending from the grounded control conductor P2 by way of RAZZ and the winding of R250 to battery. When energized over the above-traced circuit, the control relay R250 operates to complete, at RA25I, obvious multiple circuits for energizing the lower windings of the lockout relays in the various line circuits, thereby to cause the last-mentioned relays in the various line circuits to operate.

When the lockout relay Ri35 in the line cuit |30 individually associated with the box line I00 operates, it completes, at RAME, the previously mentioned holding circuit for energizing in series the upper winding of the loci;- out relay RISE and the lower winding of the impulse relay Rili, this circuit extending from ground by way of RAILlI, RCI43, the upper Winding of Ri, RAl and the lower winding of RAI05 to battery. When energized over the above-traced circuit, the impulse relay R405 reoperates, thereby to cause the timing relay Ri@ and the control relay RI55 to restore as previously explained. When the timing relay RIS@ and the control relay RI55 in the line circuiti-30 restore, the previously traced circuits for energizing the start relay R2 I0 and the rst impulse relay R220 in the repeater 200 are interrupted, thereby to cause the relays to restore as previously explained. Upon restoring, the first impulse relay R220 interrupts, at RA222, the previously traced path for applying battery potential to the control conductor PI, thereby to cause the operation of the timing apparatus 'I'A associated with the control conductor PI to be arrested and to interrupt the previously traced circuit for energizing the upper winding of the test relay R240. Also, upon restoring, the rst impulse relay R220 interrupts, at RAZZS, the previously traced holding circuit for energizing the lower winding of the test relay RZil. The test relay R240 then restores to interrupt, at RA242, the previously traced circuit for energizing the winding of the control relay R250, whereupon the latter relay restores. Upon restoring, the control reiay R250 interrupts, at RAiiiI, the previously mentioned multiple circuits for energizing the lower windings of the lockout relays in the various line circuits.

It is noted that, upon operating, only the lockout relay Ril in the line circuit i3d individually associated with the faulty box line 00 completes a holding circuit for energizing the upper winding thereof in series with the lower winding of the associated impulse relay, due to the fact that only the associated line relay Rlli occupies its restored position at this time. For example, when the lockout relay Rl in the line circuit |60 individually associated with the combination cirbox and alarm line II5 operates, it does not complete at RAIBB a holding circuit for energizing the upper winding thereof in series with the lower winding of the impulse relay RI'IS, due

lto the fact that the associated line relay RI'IiJ occupies its operated position, thereby tovretain interrupted, at RAIII and RCII3, a point in the previously mentioned holding circuit for energizing the upper winding of the lockout relay RI65 in series with the lower winding of the impulse relay RI'I5. Accordingly, when the control relay R250 in the repeater 200 restores to interrupt, at RA25I, the previously mentioned multiple circuits for energizing the lower windings of the lockout relays in the various line circuits, all of the lockout relays restore, with the exception of the lockout relay RI35 in the line circuit I30 individually associatedwith the faulty box line |00. At this time the faulty box line is locked out of service by the operated lockout relay RI35 in the associated line circuit I30; and the repeater 200, the remainder of the box lines, the combination box and alarm lines and the alarm trunk 33|V are idle and available `for further use.

It is noted that the faulty box line |00 will remain locked out of service until it is repaired, at which time the previously traced series circuit including the box line |00 will be recompleted, thereby to cause the line relay RI40 in the line circuit |30 individually associated with the box line |00 to reoperate. When the line relay RME] reoperates, it interrupts, at RAMI and RCI43, the previously traced holding circuitfor energizing the upper winding of the lockout relay RI35 in series with the lower winding of the impulse relay R545 and completes, at RAMI and RCI42, the previously mentioned original circuit for energizing the lower winding of the impulse relay R445, whereupon the lockout relay RI35 restores and the impulse relay RI K remains in its operated position.

In view of the foregoing description of the operation of the arrangement for locking the faulty box line I0@ out of service, it will be understood that other faulty box lines or any one of the combination box and alarm lines which is faulty will be locked out of service by the operation of the arrangement in a similar manner. l

Furthermore, it is noted that this arrangement is so connected and arranged that the alarm trunk 30| may be locked out of service in the event that it fails due to an open circuit fault thereon.

In the event that the alarm trunkSI is interf rupted, the line circuit 320 individually associated therewith operates, in the previously described manner, thereby to cause the start relay R2I0 R240 and RA234 to the control conductor PI.

Furthermore, the second impulse relay R230 prepares, at RA235, an alternative holding circuit :for energizing the lower winding of the test relay R240. Under these conditions, the second impulse relay'R230 does not alternately operate and `restore -due to the fact that no impulses are being transmitted over the alarm trunk 30I. Y Accordingly, the timing apparatus TA265 associated flO with the control conductor PI operates after a predetermined time interval, thereby to complete an alternative circuit for energizing the upper winding of the test relay R240. extends from ground potential appearing upon the control conductor PI by way of RA234 and the upper winding of R240 to battery. yWhen energized over the above-traced circuit, the test relay R243 operates to complete, at RA24I, the previously mentioned alternative holding circuit for energizing the lower winding thereof, this circuit extending from ground by way of RA235, RAZM and the lower winding of R240 to battery. Also, upon operating, the test relay R240 prepares, at RA242, the previously traced circuit for energizing the winding of the control relay R250, which circuit is completed, after ,a predetermined time interval, by the operation of the timing apparatus TA285 associated with the conrol conductor Pi, thereby to cause the control relay R250 to operate as previously explained. Upon operating, the control relay R250 cornpletes, at RA25I, the previously mentioned multiple circuits for energizing the lower windings of the lockout relays in the various line circuits as previously explained. At this time the lockout relay R350 in the line circuit 320 individually associated with the alarm trunk I completes, at RAI, upon operating, a holding circuit for energizing the upper winding thereof in series with the lower winding of the impulse relay R340. This circuit extends from ground b-y way of RA343, RC348, the upper winding of R350,

YRASI and the lower winding of R340 to battery.

When the last-mentioned circuit is completed, the lockout relay R350 is retained in its operated position and the impulse relay R340 operates. At this time only the lockout relay R350 in the line circuit 323 individually associated with the faulty alarm trunk 30| operates to complete a holding circuit for energizing the upper winding thereof in series with the associated impulse relay, due to the fact that only the associated line relay R345 occupies its restored position at this time as previously explained. Upon operating,

the impulse relay R340 causes the timing relay R335 and the control relay R330 to restore as previously explained, whereupon the' previously traced circuits for energizing the start relay R2 I 0 and the second impulse relay R230 in the repeater 230 restore. When the start relay RZIU and the second impulse relay R230 restore, the

-repeater 200, each of the box lines and cach of the combination box and alarm lines are rendered idle. Although alarms initiated on the various box lines and on the various combination box and alarm lines are not repeated by way of Vthe faulty alarm trunk 30I to the central oiiice Y5l? at this time, these alarms are repeated by the repeater 200 over the various combination box and alarm lines. Accordingly, the signaling system is not rendered completely inoperative even though the alarm trunk 30I extending between the central office and the repeater 200 vat the repeater station fails due to an open circuit fault thereon.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that `various modifications may be made therein, and fit is intended to cover in the appended claims This circuit v all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

l. In a signaling system, a plurality of stations, a repeater, a plurality of lines respectively extending between said stations and said repeater, a sender at each of said stations operative to send a signal over the associated line, relays individually associated with said lines, each of said relays being provided With an operating circuit and a holding circuit, means for controlling the operating circuit of each of said relays in accordance with a signal sent over the associated line, thereby normally to cause the relay to operate intermittently, means controlled by the intermittent operation of any one of said relays for completing the holding circuits of the other of said relays, thereby to prevent intermittent operation of said other relays, a repeating device included in said repeater, and means for controlling said repeating device in accordance with the intermittent operation of said one relay.

2. In a signaling system, a plurality of stations, a repeater, a plurality of lines respectively extending between said stations and said repeater, an impulse sender at each of said stations operative to send impulses over 'the associated line, impulse relays and timing relays individually associated with said lines, each of said impulse relays being provided with an operating circuit and a holding circuit, means lor controlling the operating circuit of each of said impulse relays in accordance with impulses sent over the associated line, thereby normally to cause the impulse relay to operate intermittently, means controlled by the intermittent operation of any one of said impulse relays for controlling the associated one of said timing relays, means controlled by said one timing relay for interrupting a point in the holding circuit of said one impulse relay and for completing the holding circuits of the other of said impulse relays, thereby to prevent intermittent operation of said other impulse relays, a repeating device included in said repeater, means for controlling said repeating device in accordance with the intermittent operation of said one impulse relay, and means controlled by said one timing relay after the impulses have been sent over the associated line for interrupting the holding circuits of said other impulse relays.

3. In a signaling system, a plurality of stations, a repeater, a plurality of lines respectively extending between said stations and said repeater, an impulse sender at each of said stations operative to send impulses over the associated line, impulse relays individually associated with said lines, each of said impulse relays being provided with a normally completed operating circuit and a normally interrupted holding circuit, means for controlling the operating circuit of each of said impulse relays in accordance-with impulses sent over the associated line, thereby to cause the impulse relay to restore intermittently, means for interrupting the operating circuit of each of said impulse relays in the event the associatedline is subjected to an open circuit fault, thereby to cause the impulse relay to remain restored, means controlled by the restoration of any one of said impulse relays for interrupting a point in the holding circuit of said one impulse relay and for completing the holding circuits of the other of said impulse relays, thereby to prevent restoration of said other impulse relays, a repeating device included in said repeater, means for controlling said repeating device in accordance with the intermittent operation of said one impulse relay, means including a timer controlled in the event said one impulse relay remains restored a predetermined time interval for completing the holding circuit of said one impulse relay, and means controlled when the line associated with said one impulse relay is recompleted for interrupting the holding circuit of said one impulse relay.

4. In a signaling system, a plurality of stations, a repeater, a plurality of lines respectively extending between said stations and said repeater, an impulse sender at each of said stations operative to send impulses over the associated line, impulse relays and timing relays individually associated with said lines, each of said impulse relays being provided with a normally completed operating circuit and a normally interrupted holding circuit, each of said timing relays being provided With an operating circuit, means for controlling the operating circuit of each of said impulse relays in accordance with impulses sent over the associated line, thereby to cause the impulse relay to restore intermittently, means for interrupting the operating circuit of each of said impulse relays in the event the associated line is subjected to an open circuit ault, thereby to cause the impulse relay to remain restored, means controlled by the restoration of any one of said impulse relays for completing the operating circuit of the associated one of said timing relays, thereby to cause said one timing relay to operate, means controlled by the operation of said one timing relay for interrupting a point in the holding circuit of said one impulse relay and for completing the holding circuits of the other of said impulse relays, thereby to prevent restoration of said other impulse relays, a repeating device included in said repeater, means for controlling said repeating device in accordance with the intermittent operation of said one impulse relay, means controlled by the restoration of said one timing relay after the impulses have been sent over the associated line for interrupting the holding circuits of said other impulse relays, means including a timer controlled in the event said one impulse relay remains restored a predetermined time interval for completing the holding circuit of said one impulse relay, and means controlled when the line associated with said one impulse relay is recompleted for interrupting the holding circuit of said one impulse relay.

5. In a` signaling system, rst and second groups of signal lines, a trunk line, each signal line in said second group and said trunk line having a receiver individually associated therewith, each signal line in each of said groups having at least one sender individually associated therewith, each o said senders including normally eiective means for sending a signal over the associated signal line and means governed when a signal is being sent over the associated signal line for rendering ineiective said last-mentioned means, a repeater commonly associated with each and means included in said repeater for receiving a signal sent over any signal line in said rst group and for repeating the signal only over the signal lines in said second group and over said trunk line and for receiving a signal sent over any signal line in said second group and for repeating the signal only over the other signal lines in said second group and over said trunk line.

A 6. In a signaling system, rst and second groups of signal lines, a trunk line, each signal line in said first and second groups and said trunk line having a receiver individually associated therewith, means for sending a signal over said trunk line, each signal line in said rst group having at least one sender individually associated therewith, each of said senders including normally elective means for sending a signal over the associated signal line and means governed when a signal is being sent over the associated signal line for rendering ineffective said last-mentioned means, a repeater commonly associated with each of said groups of signal lines and said trunk line, and means included in said repeater for receiving a signal sent over any signal line in said rst group and for repeating the signal only over the signal lines in said second group and over said trunk line and for receiving a signal sent over said trunk line and for repeating the signal over the signal lines in said first and said second groups.

7. In a signaling system, first and second groups of signal lines, a trunk line, each signal line in said first and second groups and said trunk line having a receiver individually associated therewith, means for sending a signal over said trunk line, each signal line in said second group having at least one sender individually associated therewith, each of said senders including normally elective means for sending a signal over the associated signal line and means governed when a signal is being sent over the assoing the signal only over the other signal lines insaid second group and over said trunk line and for receiving a signal sent over said trunk line and for repeating the signal over the signal lines in said rst and said second groups.

CLARENCE E. LOMAX. 

